President Trump punched back at North Korean dictator, Kim Jong-Un, in a Twitter post Saturday evening, after learning that Kim had called him “fat.”

It started while Trump was speaking in front of South Korea’s National Assembly Wednesday morning, and aimed his remarks directly at Kim Jong-Un.

“Today, I hope I speak not only for our countries but for all civilized nations when I say to the North: Do not underestimate us. And do not try us,” Trump warned. “The weapons you are acquiring are not making you safer, they are putting your regime in grave danger. We will defend our common security, our shared prosperity, and our sacred liberty.”

Kim Jong-Un lashed out in response:

“The U.S. must oust the lunatic old man from power and withdraw the hostile policy towards [North Korea] at once in order to get rid of the abyss of doom,” according to a statement from the hermit kingdom, the state-run Korean Central News Agency said Wednesday. “The U.S. had better make a decisive choice…if it does not want a horrible nuclear disaster and tragic doom.”

Saturday evening, Trump tweeted sarcastically, “Why would Kim Jong-un insult me by calling me “old,” when I would NEVER call him “short and fat?” Oh well, I try so hard to be his friend – and maybe someday that will happen!”